1. Field of the Invention
This invention relates to antipathogenic compounds and methods for their use.
2. Description of Related Art
A number of naturally occurring or synthetic compounds bind to double stranded nucleic acid, especially double stranded DNA (“dsDNA”). Some bind to the major groove, while others bind to the minor groove. Still others intercalate between adjacent base pairs. Combination binding modes are known, in which a compound has binding interactions with more than one nucleic acid site.
It has been proposed to use dsDNA binding compounds to regulate the expression of genes for medical purposes. If a disease is characterized by the overexpression or undesired expression of a gene (e.g., an oncogene), in principle the disease can be treated by suppressing wholly or partially the gene's expression via the binding of a compound to the gene or a promoter site thereof and interfering with transcription. Infections by pathogens such as fungi, bacteria, and viruses can be treated with compounds that interfere with the expression of genes essential for the pathogen's proliferation. Or, in a disease characterized by non- or under-expression of a beneficial gene, the expression of the beneficial gene can be up-regulated with a compound that binds to the binding site of a repressor, displacing the repressor.
The natural products distamycin and netropsin represent a class of DNA-binding compounds that has been studied over the years:
Structurally, distamycin and netropsin are heteroaromatic polyamides, having as their core structural motif N-methylpyrrole carboxamide residues. They bind to the minor groove, their crescent molecular shapes providing a conformational fit within the groove. The binding occurs with a preference for A,T rich dsDNA tracts.
Many heteroaromatic polyamides have been synthesized elaborating on the distamycin/netropsin motif, with the objective of enhancing or varying biological activity, increasing binding affinity to dsDNA, and/or improving specificity in base pair sequence recognition. See Bailly et al., Bioconjugate Chemistry 1998, 9 (5), 513-538, and Neidle, Nat. Prod. Rep. 2001, 18, 291-309. The use of synthetic heteroaromatic polyamides in therapeutics has been proposed, for example, in Dervan et al., U.S, Pat. No. 5,998,140 (1999); Dervan et al., WO 00/15209 (2000); Dervan, WO 00/15773 (2000); and Gottesfeld et al., WO 98/35702 (1998).